The current study was conducted to examine the microstructure of the 2 pct Mg-55 pct Al-1.6 pct Si-Zn (wt pct) coating on steel in detail and analyse the formation mechanisms of various reaction products in the coating. The coating microstructure was comprised of an α-Al dendrite framework, and an interdendritic network, occupied by a number of solidification products, which were fine Al-Zn mixtures, Mg₂Si, Si, MgZn₂, and lamellar MgZn₂/Zn mixtures. It was found that the Al-Zn mixtures observed in the interdendritic region were the decomposition products of the high Zn α-Al components of various eutectic reactions taking place during solidification. A method was developed to differentiate the Si and Mg₂Si phases optically with colour contrasts. It was found that, when Si and Mg₂Si formed, they occupied the entire interdendritic spaces at the locations where they formed. Judging from the Al-Mg-Si liquidus projection, the Mg₂Si phase should form first during solidification, followed by the simultaneous formation of Mg₂Si and Si. On the other hand, the MgZn₂ phase formed into two different morphologies, with a large blocky shape and fine precipitates embedded in the lamellar Zn/MgZn₂ mixtures, both surrounded by Al-Zn mixtures. It was observed that all eutectic reactions involved the formation of an α-Al component, which formed in a divorced manner via either growing on existing dendrite arms, or sometimes as isolated islands embedded in blocky MgZn₂.

进行当前的研究以详细检查钢上2 pct Mg-55 pct Al-1.6 pct Si-Zn（wt pct）涂层的微观结构，并分析涂层中各种反应产物的形成机理。涂层的微观结构由一个α- Al枝晶骨架和一个枝晶网络组成，被许多凝固产物占据，这些凝固产物是细小的Al-Zn混合物，Mg ₂ Si，Si，MgZn ₂和层状MgZn ₂ / Zn混合物。发现在枝晶间区域观察到的Al-Zn混合物是凝固期间发生的各种共晶反应的高Znα - Al组分的分解产物。开发了一种区分硅和镁的方法_2个Si相在光学上具有颜色对比。发现，当Si和Mg ₂ Si形成时，它们在它们形成的位置处占据了整个树突间空间。从Al-Mg-Si液相线投影来看，应在凝固过程中首先形成Mg ₂ Si相，然后同时形成Mg ₂ Si和Si。另一方面，MgZn ₂相形成两种不同的形态，具有大的块状形状，并且细微的沉淀物嵌入层状的Zn / MgZn ₂混合物中，两者均被Al-Zn混合物包围。观察到所有共晶反应都涉及α- Al组分的形成，该α- Al组分通过要么生长在现有的枝晶臂上，要么有时是嵌入在块状MgZn _2中的孤立岛。